First Alert Weather: More Heat, Humidity Leads to Stormy Threat

What to Know

Storms arrived in the Philadelphia region Monday evening, bringing along the threat of damaging winds, heavy rain and lightning strikes.
An isolated tornado and larger hail couldn't be ruled out, especially in northern and western parts of the region.
A First Alert is in effect north and west of Philadelphia from 6 p.m. until 10 p.m. Monday.

Heat and humidity built up Monday afternoon and led to some strong storms in the Philadelphia region, especially neighborhoods north and west of the city.

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The NBC10 First Alert Weather Team issued a First Alert for storms packing a threat for damaging winds, heavy rain and lightning from 6 p.m. until 10 p.m. Monday for Philadelphia, the Pennsylvania suburbs, Mercer County, northern Delaware, Berks County and the Lehigh Valley. An isolated tornado and some larger hail couldn't be ruled out.

These storms, riding on a cold front, are expected to weaken after passing the I-95 Corridor from the west. The greatest impact from the storms could reach into Philadelphia and surrounding suburbs from Wilmington to Trenton.

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Temperatures on Monday pushed into the low 90s in Philadelphia -- bringing along the second heat wave of the season -- before the storms arrived. A heat advisory was in effect during the day for Philadelphia and the surrounding communities as it felt like the upper 90s.

The heat, however, will break after the Monday night storms and another round of rain and some spotty storms on Tuesday from late morning through the afternoon. The high on Tuesday is only expected in the mid to upper 70s.